A product of Keebra Park High School, Marshall played junior representative football for Australia in both touch football and rugby league with the 2003 Australian Schoolboys. Although eligible for the Kangaroos, Marshall would declare his allegiance to New Zealand at a young age.

Marshall would make his first-grade debut for Wests Tigers in 2003, coming off the bench to play fullback in a dominant win for his side over Newcastle Knights. He would go on to play just three more games that season, given he was still studying at high school.

Helping Wests Tigers win the pre-season Sevens tournament in 2004, Marshall would suffer a dislocated shoulder twice throughout the year, before returning to the team full-time in 2005. That year, he would star as Tim Sheens’ side took the NRL by storm to clinch the club’s maiden premiership — famously setting up Pat Richards with the iconic flick pass in the Grand Final win over North Queensland.

Marshall would make his international debut for New Zealand that year in the ANZAC Test, while also featuring in the end-of-season Tri Nations.

Injuries would continue to hamper Marshall throughout 2006 and 2007, suffering dislocated and fractured shoulders on a number of occasions. He suffered a knee ligament tear in Round 3 of 2008, before returning later that year to help guide New Zealand to their first ever World Cup win.

Switching between halfback and five-eighth, Marshall’s game would reach new heights over the next few years. He was named as captain of New Zealand in 2009, before being named as the Five-Eighth of the Year by the Rugby League International Federation.

In 2010, Marshall became the club’s all-time top try-scorer (surpassing Daniel Fitzhenry) and a contract extension with the club that kept him at Wests Tigers until the end of 2015. He featured for the NRL All Stars as captain of New Zealand, before going on to feature in every game throughout the year for the first time in his career.

Marshall was named Man of the Match in the Kiwis Four Nations win over Australia later that year, and continued to receive individual accolades with the Golden Boot Award for the best rugby league player in the world. He remains the only Wests Tigers player to have ever won this award.

The fleet-footed playmaker was named Halfback of the Year in 2011 by the Rugby League International Federation — a year that saw him finish as the top points scorer in the NRL and also surpass Brett Hodgson as the club’s all-time top points-scorer.

In 2012, Marshall again played every game for Wests Tigers and led the league in both try assists and line break assists. He captained the NRL All Stars to victory, was nominated as the Dally M Halfback of the Year, became the first player in club history to record 1000 points in the NRL and also broke the record for most appearances as New Zealand captain (20).

He would announce his decision to leave Wests Tigers the following year as he made the switch to rugby union with the Auckland Blues, before returning to the NRL in 2014 with the St. George-Illawarra Dragons. He would help the Dragons to an Elimination Final appearance in 2015, a year that saw him re-establish himself as a premiere playmaker with a second-placed finish in the Dally M Player of the Year voting.

Marshall played his 250th NRL game against Wests Tigers in 2016 (helping the Dragons to a comfortable victory), before signing with the Brisbane Broncos in 2017. Again, he helped the team to the finals — this time going down to the Melbourne Storm in the Preliminary Final.

In August that year, Marshall would confirm he was returning to Wests Tigers in 2018 to finish his career where it all began. An injury to Josh Reynolds on the eve of Round 1 saw the veteran playmaker thrust in to the starting role, with his experience helping Wests Tigers down the Sydney Roosters for the first time since 2011. Reynolds’ unavailability throughout the year saw Marshall feature in 21 games for Wests Tigers, more than many expected prior to the year, with the five-eighth making more tackles than in any other season in his career.

He would announce his decision to re-sign with Wests Tigers for one more season, retiring at the end of 2019. He is currently the third most capped player in Wests Tigers history, and could reach the illustrious 300-game club in 2019 (currently on 289 career appearances).